As Drug Enforcement Administration officials warn of the threat of legalizing marijuana and insist that it's one of the "most dangerous" controlled substances out there, along the lines of heroin and LSD, their claims are being undermined by an unlikely source: the agency's very own drug policy.

Under the DEA's hiring rules, an applicant for any agency position who admits to or is found to have used narcotics or dangerous drugs is not considered for employment. Any past use of heroin, LSD, cocaine, or even Adderall without a prescription immediately disqualifies an applicant for a job at the DEA.

The DEA's one-and-only exception to the stringent policy? Marijuana.

Applicants who admit to "limited youthful and experimental use of marijuana" may get an exception from the policy, making it the single controlled substance that the DEA implicitly admits isn't as bad as all other illegal drugs.

The DEA policy dates back at least seven years, as it was noted in a 2007 story about the FBI deciding to relax its own drug policy.